This research explores the potential of retinal ganglion cells (RGCs), particularly intrinsically photosensitive RGCs (ipRGCs), as biomarkers for predicting response to transcranial magnetic stimulation (TMS) in treatment-resistant depression (TRD). We also aim to assess the impact of TMS treatment on RGCs and ipRGCs in TRD patients, investigating associations with clinical improvements and cognitive status. A clinical trial involving 44 patients with treatment-resistant depression (TRD) will be conducted. All participants will receive rTMS targeting the dorsolateral prefrontal cortex (DLPFC). Data will be collected pre- and post-intervention, as well as at a 2-month follow-up, using multiple outcome measures, including the post-illumination pupil response (PIPR). The project seeks to confirm the effectiveness of TMS and the potential of RGCs/ipRGCs as predictors of treatment response, thereby facilitating the development of personalized treatment strategies for TRD patients undergoing rTMS therapy.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
44
Each participant's resting motor threshold (RMT) will be determined by visual observation in accordance with standard clinical practice. Intermittent theta-burst stimulation (iTBS) will be delivered over the left dorsolateral prefrontal cortex (DLPFC) using these parameters: stimulation intensity 120% RMT; bursts at 50 Hz; 2 s on and 8 s off; 600 pulses per session; total stimulation time approximately 3 minutes per session. Stimulation will be delivered using a MagPro X100 stimulator with MagOption, equipped with a B70 butterfly-shaped coil with static cooling (MagVenture, Denmark). Treatment will comprise 20 sessions, delivered once daily on weekdays.
RISE-Health, Center for Translational Health and Medical Biotechnology Research (TBIO), School of Health, Polytechnic of Porto
Porto, Porto District, Portugal
RECRUITINGChromatic pupillometry
To extract post-illumination pupil response (PIPR) derived from ipRGCs
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Optical Coherence Tomography (OCT)
To extract central retinal thickness and thicknesses of retina neuronal layers (GCL-IPL and RNFL)
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Pattern Electroretinogram (PERG)
To extract PERG N95 wave related to RGC function.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Contrast sensitivity test
To measure contrast sensitivity
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Montgomery-Åsberg Depression Rating Scale (MADRS)
To evaluate treatment response. Scores range from 0 to 60, with higher scores indicating more severe depressive symptoms.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Maudsley Staging Depression
To assess the level of treatment resistance in depression. Scores range from 3 to 15, with higher scores indicating greater treatment resistance.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
California Verbal Learning Test-II (CVLT-II)
To assess verbal learning and memory. Scores range from 0 to 80, with higher scores indicating better verbal learning and memory performance.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Reading Mind in Eyes Test (RMET)
To assess social cognition and theory of mind through recognition of mental states from images of the eye region. Scores range from 0 to 36, with higher scores indicating better social cognitive performance.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Symbol Digit Modalities Test (SDMT)
To assess information processing speed and attention. Scores range from 0 to 110, with higher scores indicating better cognitive processing speed performance.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
Brief Visuospatial Memory Test-Revised (BVMT-R)
To assess visuospatial learning and memory. Scores range from 0 to 36, with higher scores indicating better visuospatial memory performance.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
WHODAS 12-item (Self-report)
To assess disability and functional impairment in daily life. Scores range from 12 to 60, with higher scores indicating greater disability.
Time frame: Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention)
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